Safety device for quick coupler

Abstract

The present invention relates to a safety device for a quick coupler and, more particularly, to a safety device for a quick coupler, the safety device having an improved structure that is configured to improve the structure of a locking device, the locking device preventing the fixing hook from being arbitrarily released from a locking engagement, by using a safety plate that is laterally moved in a sliding manner by an elastic force of a DIE spring after a fixing hook and a first attachment pin are assembled together.

The invention claimed is: 
     
       1. A safety device for a quick coupler, the safety device comprising:
 a quick coupler body configured to be connected to an arm of an excavator; 
 a fixing hook provided at a first side of the quick coupler body, engaged with a first attachment pin, and provided with a stopping protrusion having an opening-side end portion protruding upwardly; 
 a hitch provided at a second side of the quick coupler body, and connected to a cylinder rod of a main-cylinder to be engaged with a second attachment pin when the cylinder rod performs forward operation; and 
 a first locking means for preventing locking engagement between the fixing hook and the first attachment pin from being arbitrarily released, 
 wherein the first locking means comprises: 
 a first support plate fixed to the quick coupler body; 
 a sub-cylinder mounted to the first support plate in which a sub-rod is retracted; 
 a moving plate having a first support step that is connected to the sub-rod and a safety plate at a lower surface of the moving plate, and disposed to be moveable in a sliding manner toward an upper side of the fixing hook; and 
 at least one DIE-spring fixed to the first support plate by a support means, and transmitting an elastic force to allow the moving plate to be positioned at the upper side of the fixing hook, and 
 wherein the support means comprises: 
 a support bolt passing through the DIE-spring to be locked to the first support plate and to support a first end of the DIE-spring; and 
 a locking step protruding from an upper surface of the moving plate, coupled to the support bolt that passes therethrough, and supporting a second end of the DIE-spring. 
 
     
     
       2. The safety device of  claim 1 , wherein the DIE-spring comprises a first and a second DIE-springs which are spaced apart from each other, and each of the first and second DIE-springs is a compression spring. 
     
     
       3. The safety device of  claim 1 , wherein, when the safety plate is positioned at the upper side of the fixing hook, a lower surface of the safety plate is positioned at a height where the safety plate interferes with the first attachment pin along with the stopping protrusion so that the first attachment pin is prevented from being released from engagement with the fixing hook. 
     
     
       4. The safety device of  claim 1 , wherein the quick coupler body is provided with a guide groove at opposite inner surfaces of the quick coupler body, respectively, the guide groove guiding sliding movement of the moving plate. 
     
     
       5. The safety device of  claim 1 , further comprising:
 a first elastic spring in which one end of the first elastic spring is supported by a base step provided in an outer circumference of the main-cylinder, for supplying an elastic force toward the hitch. 
 
     
     
       6. A safety device for a quick coupler, the safety device comprising:
 a quick coupler body configured to be connected to an arm of an excavator; 
 a fixing hook provided at a first side of the quick coupler body, engaged with a first attachment pin, and provided with a stopping protrusion having an opening-side end portion protruding upwardly; 
 a hitch provided at a second side of the quick coupler body, and connected to a rod member of a cylinder to be engaged with a second attachment pin when the rod member performs forward operation; and 
 a second locking means for preventing engagement between the fixing hook and the first attachment pin from being arbitrarily released, 
 wherein the second locking means comprises: 
 a second support plate fixed to a first side of the quick coupler body; 
 a support bolt in which one end portion of the support bolt is locked to the second support plate; 
 a stop block having a second support step at an upper part of the stop block thereby allowing the support bolt to pass therethrough, with a blocking portion protruding downwardly from a lower part thereof; 
 a support spring coupled to the support bolt, supported by a head portion of the support bolt and the second support step, and having an elastic force to push the stop block toward an upper side of the fixing hook; and 
 a transport means for moving an outer cylinder block connected to a cylinder housing of the cylinder during clockwise rotation of the hitch, to move the stop block toward the upper side of the fixing hook depending on movement of the outer cylinder block, and 
 wherein the transport means comprises: 
 a frame pin coupled to the first side of the quick coupler body and coupled to an end of the cylinder housing to rotate the cylinder; 
 a stopper fixed to the second side of the quick coupler body, and limiting a rotational angle of the hitch when the rod member is retracted; 
 the outer cylinder block covering the cylinder housing, configured to move in a sliding manner toward the hitch from the frame pin when the stopper restricts rotation of the hitch due to the retracted rod member, and configured to move toward the frame pin when the rod member is extended; 
 an inner cylinder block disposed to cover the rod member in which a first side of the inner cylinder block is connected to the hitch by a pin and a second side thereof is disposed inside the outer cylinder block; 
 a first link member in which a first side of the first link member is connected to the outer cylinder block so that the first link member and the outer cylinder block are configured to move in conjunction with each other; and 
 a second link member in which a first side of the second link member is connected to a second side of the first link member by a sliding pin and a second side thereof is integrally connected to the stop block. 
 
     
     
       7. The safety device of  claim 6 , wherein, when the stop block is positioned at the upper side of the fixing hook, a lower surface of the blocking portion is positioned at a height at which the blocking portion interferes with the first attachment pin along with the stopping protrusion so that the first attachment pin is prevented from being released from engagement with the fixing hook. 
     
     
       8. The safety device of  claim 6 , wherein the quick coupler body is provided with a guide groove at each of opposite inner surfaces of the quick coupler body, the guide groove supporting opposite portions of the stop block and guiding lateral sliding movement of the stop block. 
     
     
       9. The safety device of  claim 6 , further comprising:
 a second elastic spring in which a first end of the second elastic spring is supported by a base step provided in an outer circumference of the cylinder housing and a second end thereof is supported by the inner cylinder block, for supplying an elastic force toward the hitch.